Generally described, computing devices utilize a communication network, or a series of communication networks, to exchange data. Companies and organizations operate computer networks that interconnect a number of computing devices to support operations or provide services to third parties. The computing systems can be located in a single geographic location or located in multiple, distinct geographic locations (e.g., interconnected via private or public communication networks). These computing systems can be interconnected to form what may be referred to as “content delivery networks” (CDNs) or content delivery systems.
Content providers (such as businesses, artists, media distribution services, etc.) can use these CDNs to delivery content in the form of data objects (e.g., representing web sites, web content, or other digital data) to users or clients. Existing routing and addressing technologies can enable multiple computer systems associated with a content delivery system to provide similar or identical data objects to client computing devices. In some instances, a location providing a set of data objects may be referred to as a point-of-presence (“POP”). A content delivery system can maintain POPs over a wide area (or worldwide) to enable the system to efficiently service requests from clients in a variety of locations. A POP within the CDN can maintain all or a portion of the data objects provided by an origin server (e.g., within a data store of the CDN). When a client requests a data object from a POP, the POP can determine whether the requested data object is maintained at the POP. If so, the POP can provide the requested data object to the client directly. If not, the POP may first retrieve the data object from the origin server, and thereafter provide the data object to the client.